Cell is unlocked Samsung SGH-J165L from Brazil, sold by the VIVO wireless company (4 band, 3G). Not available in USA.
Wireless provider is now AT&T.
Phone has been used successfully with AT&T, VIVO, and OI SIMs (last 2 are in Brazil).

Everything works fine except unable to download ringtones or apps from AT&T Media Mall, MobiTV website, or 3rd party websites. Internet browsing also works fine.

What is the likely cause for this problem (IMEI number not recognized by websites, firmware customized to work only with VIVO website, or other item-please specify)?

Thanks in advance

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